Help in using Analog Multiplier

Discussion in 'The Projects Forum' started by krishnaagarwala, Apr 26, 2010.

  1. krishnaagarwala

    Thread Starter New Member

    Apr 7, 2010
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    Hii...I am working on a project on MPPT of solar panel and have to an ANALOG MULTIPLIER for power calculation in the control circuit.

    I used MPY634 for the multiplier according to the datasheet.
    X1- 5V; X2- Gnd; Y1- 5V; Y2- Gnd; SF- N.C; Z2- Gnd; Z1 connected to Output pin; Vs: +/-15V.

    However i didn't get the desired output, what i got was a DC level of approx 13.4V as output.

    The output remained the same even when input dc levels were changed and even when input was made AC.

    I think i am going wrong somewhere...and am not using the multiplier properly.

    Plz help.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    It sounds like the MPY634 is having a problem. That level is probably the maximum positive output. We would need an accurate schematic to see what might be wrong.
     
  3. krishnaagarwala

    Thread Starter New Member

    Apr 7, 2010
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    hii..
    the schematics of the MPPT has been uploaded.

    i used MPY634 instead of AD633(not avl)..and m hving prblms as stated above...plz help..!!
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    282
    There are no values for the components. There is no way to see what the voltage and current output might be for the array, or to see what the op amps might be doing.

    A theory of operation would be helpful- that's a detailed explanation of the circuit function, including what the output is supposed to do. None of that is clear from the schematic.
     
  5. krishnaagarwala

    Thread Starter New Member

    Apr 7, 2010
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    The main circuit is a buck convereter that is designed to provide a fixed dc output as the output of pv array is never constant(depending upon insolation levels).The PV array open circuit voltage is around 24V max....and the current o/p is 4A max.The control circuit is designed to compare Voltage and Power level of the array to check whether its working around its maximum power point or not.The voltage and current followers are used to sense respective values. The voltage sensed is then multiplied(using AD633 or MPY634) by current to give instant power. The resulting voltage and power levels are then differentiated and compared to ground and seen whether the change is +ve or -ve and then considerable logic follows to switch the converter.
     
  6. krishnaagarwala

    Thread Starter New Member

    Apr 7, 2010
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